A passivation film (or layer) deactivates chemically and electrically active broken bonds at a semiconductor surface by reacting with selected elements; e.g. hydrogen or oxide grown on Si surface. Some integrated circuit devices have a passivation film over metal layers.
Integrated circuits including the passivation film are put under product qualification tests such as High Temperature Reverse Bias (HTRB) and/or Pressure Cooker Test (PCT). HTRB testing is an accelerated life-test for integrated circuit devices that is often used to verify the robustness of the devices themselves and the reliability of assembly and packaging of the integrated circuit devices. PCT tests water/moisture resistance at test conditions of high temperature and high pressure.
With some passivation films, mobile ions from molding compound are driven into the passivation films, and moisture can be ionized between the molding compound and the passivation film under HTRB test. These ions cannot be easily neutralized if the passivation film is a good insulator. These mobile ions can degrade the breakdown voltage (BV) of the devices.